<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <script>
    let stu1 = [88,49,30,20,10]
    let stu2 = [80,69,39]
    let stu3 = [28,39,30,50]
    function getSum(arr = []){
      let sum = 0
      for(let i = 0; i< arr.length ;i++){
        sum+=arr[i]
      }
      return sum
    }
  console.log(getSum(stu1))
  console.log(getSum(stu2))
  console.log(getSum(stu3))
  console.log(getSum())
  </script>
</body>
</html>